3 posts • Page 1 of 1
p\Pure liquids and pure solids have activities that are one (they don't appear in the mass action expression). Thus if you add more of them they will not affect the equilibrium at all. Solubility is a situation like this. If you have a saturated solution and you add more solid nothing happens (the reaction does not shift to the right even though you have added more reactant). You need to change the concentrations or pressures in the mass action expression to affect the equilibrium.
For K and Q, you are typically using the concentrations or partial pressures of the chemical species to write those expressions. But it's very difficult to define or even measure the concentrations or partial pressures of pure solids and pure liquids. It's much clearer how to measure the concentrations or partial pressures of gases and aqueous solutions. :)
Who is online
Users browsing this forum: No registered users and 1 guest